The White House declined to comment on the Post report, saying it was an intelligence matter. The Department of State also declined to comment. Saudi Arabia's top diplomat says Crown Prince Mohammed had "absolutely" nothing to do with the killing.
The CIA believes Saudi Crown Prince Mohammed bin Salman ordered the killing of journalist Jamal Khashoggi in Istanbul, US media and news wires reported on Friday, complicating President Donald Trump's efforts to preserve ties with a key US ally.
The CIA's finding, first reported by the Washington Post, is the most definitive US assessment to date tying Saudi Arabia's de facto ruler directly to the killing.
One source said the CIA had briefed other parts of the US government on its assessment, which contradicts Saudi government assertions that Prince Mohammed was not involved.
Both the White House and the State Department declined to comment.
Saudi Arabia's top diplomat has said the crown prince had "absolutely" nothing to do with the killing.
Khashoggi, a critic of the Saudi government and a columnist for the Washington Post, was killed at the Saudi consulate in Istanbul on October 2 when he went there to pick up documents he needed for his planned marriage to a Turkish woman.
A changing narrative of death
Khashoggi, a critic of the Saudi government, had resisted pressure from Riyadh for him to return home.
Saudi officials have said a team of 15 Saudi nationals were sent to confront Khashoggi at the consulate and that he was accidentally killed in a chokehold by men who were trying to force him to return to the kingdom.
Turkish officials have said the killing was intentional and have been pressuring Saudi Arabia to extradite those responsible to stand trial. Turkish media reported on Friday that a second recording from the day of Khashoggi's death caught the Saudi "hit squad" going over their plans to kill the journalist.
An adviser to Turkey's President Recep Tayyip Erdogan on Thursday accused Saudi Arabia of trying to cover up the murder.
His remarks came after Saudi Arabia's public prosecutor said he was seeking the death penalty for five suspects charged in Khashoggi's killing.
The Saudi prosecutor, Shalaan al Shalaan, told reporters the Saudi crown prince knew nothing of the operation, in which Khashoggi's body was dismembered and removed from the consulate.
US officials have hedged their bets, saying American and Turkish intelligence agencies do not have direct evidence linking Prince Mohammed to the assassination, New York Times reported.
The Post, citing people familiar with the matter, said the CIA reached its conclusions after examining multiple sources of intelligence, including a phone call that the prince's brother, Khalid bin Salman, the Saudi ambassador to the United States, had with Khashoggi.
Khalid told Khashoggi he should go to the Saudi consulate in Istanbul to retrieve the documents and gave him assurances that it would be safe to do so, the Post said.
As we told the Washington Post the last contact I had with Mr. Khashoggi was via text on Oct 26 2017. I never talked to him by phone and certainly never suggested he go to Turkey for any reason. I ask the US government to release any information regarding this claim.— Khalid bin Salman خالد بن سلمان (@kbsalsaud) November 16, 2018
The newspaper, citing people familiar with the call, said it was not clear if Khalid knew Khashoggi would be killed but that he made the call at his brother's direction and the call was intercepted by US intelligence.
Fatimah Baeshen, a spokesperson for the Saudi embassy in Washington, said that claim was false.
Khalid tweeted after the Post article's publication on Friday the last contact he had with Khashoggi was via text in 2017.